The invention relates generally to chromatography, and more particularly concerns application of mechanical energy to chromatographic columns and packings.
Chromatography is a general term which has been applied to techniques useful in the separation of substances, which can be gaseous, liquid, or solid in nature. Generally, the separation is due to the sample partitioning between a liquid or solid stationary phase, and a progressively moving mobile phase, which can be gaseous or liquid in nature.
The stationary phase is captive in a tube of selected interior diameter and length, which is generally called a column, and can be provided with means for introducing the moving phase and the sample, at the head of the column. Sensitive methods of determining when the separated sample components appear in the column effluent, can be instrumented to produce an electrical signal.
If the mobile phase is a gas, the technique is called Gas Chromatography, and if a liquid, the term is Liquid Chromatography. For the latter, when the column is tightly packed with a micron size particulate material requiring high solvent pump pressures, the technique can be called H.P.L.C. or high performance liquid chromatography. Equipment employing H.P.L.C. is in extensive use for both analytical and preparative techniques, in industrial, biochemical, chemical, and medical fields.
The column is an essential component in such equipment, and is very difficult to pack with the solid stationary phase, so that a minimum of voids are present. The particle size range is usually between preferred limits, and packing is achieved by introduction of a fluid slurry, and very high pump pressures. A good packing density and discrete particle size distribution, are essential requirements for efficient separations.
Need exists for a means for packing a column using much lower pump pressures, with consequent less chance of change in the particle size distribution by mechanical abrasion.
In this regard, application of much lower energy levels, and at higher frequencies to the column during a chromatographic procedure, would greatly improve the resolution, and other desirable separation parameters. Retention times would also be reduced, and solvent pump pressures greatly lowered for the same type separation, leading to constructions of improved cost efficiencies.